One of the Angels, 27-year-old South African Candice Swanepoel, submits herself to brutal ballet sessions with Mary Helen Bowers, the same tough teacher who got Natalie Portman into shape for her Oscar-winning role in 2010’s Black Swan.

Alessandra, 34, admitted: “You work out as an athlete.

“All your mind, all your everything goes into it.”

Healthy “normal” women have between 21 and 24 per cent body fat, while athletes have between 14 and 20. Anything lower and you risk organ failure and death.

Dan Roberts, who trains some of the models, told The Sun: “I treat their bodies like athletes and prepare for shows through scientifically designed nutrition and exercise plans.”

New Angel Jasmine Tookes, 24, exercises seven days a week, while Lily, 29, ramps up her exercise sessions to twice a day in the weeks leading up to the show.

Ed Razek, chief marketing officer of Victoria’s Secret, plays God, choosing who’s in and out of the show.

And, famous or not, every model is treated the same.

Kendall Jenner, who was dropped from last year’s catwalk in London amid speculation she was “too bloated”, and Gigi Hadid may be the newest recruits but their celebrity status would not have impressed Ed.

Razek has said: “You don’t get a free pass to this show, you don’t get in because you are somebody, you get in because you earned it.”

Gigi, 20, another who didn’t make the cut in 2014, has spoken of the “scary” audition process, where wannabe Angels have to parade in their underwear around Ed and a board of Victoria’s Secret executives.

Perfecting the look is vital if models want to grace the VS catwalk.

It was third time lucky for new Angel Sara Sampaio, who was linked to One Direction’s Harry Styles this year.

The Portuguese model, 24, failed the audition twice before and said “the second time I didn’t make it, it was like a knife.”

Kate Upton, who modelled for Victoria’s Secret in 2011, was dropped two years later when her relationship with the brand turned sour after casting agent, Sophia Neophitou, slated her.

She said Kate, who last year starred alongside Cameron Diaz in romcom The Other Woman, was “like a footballer’s wife, with the too-blonde hair and that kind of face that anyone with enough money could go out and buy”.

Some former stars have spoken out about the psychological damage such criticism can do.

Cameron Russell, 25, who walked for VS in 2011 and 2012, said of her fellow models: “They have the thinnest thighs and the shiniest hair and the coolest clothes and they are the most physically insecure women, probably, on the planet.”

Unpredictable working patterns also increase the stress-load — and have reportedly led to some models quitting.

As brand “ambassadors”, Angels have to commit to 50 days a year or more to support the company, which turned over £3.92billion last year.

But this could be at anytime and anywhere in the world, meaning they have to drop other lucrative work opportunities.

Aussie Miranda Kerr, 32, reportedly quit in 2013 as she could no longer commit to the demanding schedule.

The money on offer is also understood to have dropped.

Two of the most popular Angels, 23-year-old Karlie Kloss and Doutzen Kroes, 30, quit earlier this year amid rumours of pay cuts.